Accelerated bone defect repairment by carbon nitride photoelectric conversion material in core-shell nanofibrous depended on neurogenesis

Highly efficient bone repair materials are essential for the clinical treatment of large bone defects. This study aimed to develop nanofibrous scaffolds for bone defect repairment. Here, we reported that insulin like growth factor (IGF) adsorbed into phosphorus doped graphite phase carbon nitride (C3N4(P)) as core, and nerve growth factor (NGF) adsorbed into silk fibroin (SF) as shell to prepare nanofibrous scaffolds (IGF@C3N4(P)/NGF@SF) by coaxial electrospining for accelerating bone formation. Additionally, C3N4(P) was employed as a photoelectric conversion material capable of achieving the mutual conversion of light and electricity. Remarkably, we found that red light + IGF@C3N4(P)/NGF@SF scaffold may enhance osteogenesis in bone mesenchymal stem cells (BMSCs) by activating the extracellular regulated protein kinases1/2 (Erk1/2), which subsequently activated runt-related transcription factor 2 (Runx2) and the mammalian target of rapamycin (mTOR) pathway. Consequently, the mRNA expression levels of downstream osteogenic related genes were increased. Furthermore, we observed that red light + IGF@C3N4(P)/NGF@SF scaffold promoted BMSCs induced neural differentiation cells differentiated into neuron and upregulated the mRNA expression levels of neuron specific related genes. Interestingly, we also demonstrated the formation of new neurons in the Haversian canal within the cranial defect area in mice, indicating that red light + IGF@C3N4(P)/NGF@SF scaffold promoted osteogenesis with neurogenesis. Moreover, our RNA sequencing results supported the activation of neurogenesis along with osteogenesis. Based on these novel findings, we conclude that red light + IGF@C3N4(P)/NGF@SF scaffold exhibits great potential as a prospective biomaterial for promoting bone defect repairment with neurogenesis, and the utilization of red light is crucial in facilitating this process.